The Protractor Map is mostly an act of documentation, but it occasionally becomes an act of conjecture. Sometimes protractors get painted over or peeled away or broken off, and in those instances I try my best to deduce the number and color using contextual clues. (These are marked with an “x” on the Master List to signify my uncertainty.)
The best example of this so far is a run of ten numbers starting with No 131 (purple) behind West Penn Hospital and ending with No. 140 (purple) on the Bloomfield Bridge.
Of that run, half are compromised: one remains undiscovered, two have been painted over and two are broken. A purple protractor on the back of bench in Friendship Park is intact except for its number. Someone snapped it off. Given that its closer to No. 131 than to No. 134, I labeled it No. 132x in the Master List, but it could just as easily be No. 133x.
(EDIT: It is No. 133x.)
(FURTHER EDIT: No it’s not.)
What I’ve labeled No. 136x and No. 137x have both been painted over and are now solid black and solid gray, respectively. They appear on a side street between No. 135 (purple) and a half-broken purple protractor ending in the numeral 8 that I have labeled No. 138x.
And now, the sights: